A. Field of the Invention
The present invention relates to a dimensioning system that rapidly measures the dimensions of the surface of any object having any size and shape. Not only can the dimensioning system determine the dimensions of box-like objects, but it can also determine the dimensions of irregular-shaped objects such as automobile tires on a conveyor belt.
B. Description of the Prior Art
In the packaging industry, the cost of shipping often depends upon both the dimensions of an object and its weight. The procedure for assessing the shipping cost is called dimming. Because of the high volume of packages shipped, errors are often made in calculating the cost. The present invention can perform this task automatically with high accuracy for each package. Even irregularly shaped packages can be rapidly measured. The three dimensional (hereinafter “3-D”) object information can be translated into the relevant shape parameters and then combined with the package weight, if necessary, to compute the shipping cost from existing rate schedules.
A similar dimensioning procedure can be applied to manufactured objects on an assembly line. Acceptance or rejection can be determined by automatically comparing an object with a digitally stored 3-D reference shape. In addition, the invention can ascertain the minimum sized box needed to enclose an object on a conveyor belt. This application is useful if the conveyor is transporting many different objects each of which will be packaged individually.
The present invention includes a 3-D camera system using, in part, the 3-D imaging technology, which is disclosed in Stettner, et al., U.S. Pat. Nos. 5,446,529; 6,133,989 and 6,414,746 that provides, with a single pulse of light, all of the information of a conventional 2-D picture along with the third dimensional coordinates. It furnishes the 3-D coordinates of every reflective point in its field of view. The system is mechanically and optically configured so that it is useful in assembly-line machine-vision applications in which the size and shape of objects must be rapidly and accurately established.
Several methods of ascertaining the dimensions of an object and the minimum size box needed to enclose objects on a conveyor belt have been developed. However, the prior art requires many light pulses to scan an object's surface with a mechanical mechanism while the present invention obtains all dimensions by simultaneously viewing the entire surface with a single light pulse and no moving components.
U.S. Pat. No. 6,177,999 is directed to an optical scanning device which measures the height of a point on the object by directing the reflected light onto a linear CCD array as the object is swept past the device on a conveyor belt. The height of the point corresponds to a unique pixel on the CCD, measuring the object's contours point at a time.
U.S. Pat. No. 6,091,905 establishes the distance to an object by recording the total radiant energy reflected from an object during a specific length of time. A pulse of light is emitted having a pulsewidth equal to the time required for light to travel from the camera to the farthest object of interest in the scene being viewed and return to the camera. The camera observes the reflected light only during this interval. Nearby objects start reflecting earlier than farther objects and hence deliver more radiant energy to the camera during the observation interval.
U.S. Pat. No. 5,193,120 employs a video camera to image an object illuminated by many parallel lines of light simultaneously. The object's profile is enhanced by viewing the reflected light at an angle. The three-dimensional aspect of the object is derived from the image of the lines of light and the geometrical properties of the imaging system.
The system in International Publication Number WO 94/27166 calculates the height of a point on an object by measuring the time of flight required for a light beam to reflect back to the device from a point on the object. The invention moves above the object and establishes the minimum box size after many reflections.
U.S. Pat. No. 4,758,093 relies on a triangulation technique to find the surface contours of an object.